This is most likely media related.
Devices on the network can be too chatty and try to constantly discover things and speak to each other non stop, keeping the wifi awake and active.
Two big culprits:
- Spotify (uninstall or restrict all background activity?)
- Google Home devices like the Mini (turn off "Let others control your cast media")
Also check out,
Settings -> Google -> Security -> Find my Device
this might also be a suspect
Settings -> Google -> Device Connections -> Devices -> Show Notifications When devices are nearby
And then also,
Settings -> Passwords & security -> Privacy -> Location -> Google Location history
perhaps this is also scanning
I monitored the network traffic on the wifi network that the Redmi 6 running MiUi was connected to that has the drain issue.
It seems to be communicating constantly with a random laptop over the network.
It's keeping awake because of some Spotify traffic.
So I believe this is caused by media apps that try to do this whole shared network controls.
It can be related to other media devices on the network too.
There's a Google Home Mini on this network, which has this "allow other devices to control the media playback".
So turn off Spotify and Google Home devices and see if that helps.
The network broadcasting features must be draining and always keeping things awake.